The present invention relates to a device for retaining a wire-like optical wave-guide of an optical connector or the like.
Optical connectors are used at many places in optical telecommunication systems where detachable optical connection is required, such as switch-over of equipment, removal or reception transmission boards or adjustment of devices. The optical connector basically includes a sleeve or housing coaxially fitted onto the outer periphery of a wire-like optical wave-guide (e.g., an optical fiber) consisting of a core and a clad to form a first plug having a sufficiently large diameter which ensures easy handling, and another plug with a tightening fastener is then mounted on the outer periphery of the first plug. A pair of thus-obtained assemblies are coupled with each other utilizing the above-described another plugs. Alignment and coupling of the two plugs is achieved by using a receptacle with a split sleeve or a collet chuck to align a plug.
Various types of "wire-like optical wave-guide retaining devices" for use in an optical connector are known. Examples of such devices include a wire-like optical wave-guide fixed by an adhesive, and a wire-like optical wave-guide fixed by caulking.
In such retaining devices which employ the above-described conventional fixing techniques, although reliable fixing of the wire-like optical wave-guide is provided, a difference in the rate at which the optical wave-guide and the retaining member are expanded or contracted when the temperature changes, caused by a difference in coefficient of thermal expansion between the wire-like optical wave-guide and the optical wave-guide retaining member, or variations in the dimensions of the components cannot be absorbed. Consequently, an excess stress may be generated in the components of the retaining device, particularly, in the wire-like optical wave-guide, thus shortening the life of the wave-like optical wave-guide.
Furthermore, in the retaining devices employing the above-described conventional fixing techniques, if the retaining device does not conform to predetermined standards as determined by an inspection following assembly, it is impossible to disassemble the device to replace any nonconforming component. Consequently, the output is low, and production is very uneconomical.
In the case of the retaining device which employs an adhesive to fix the optical wave-guide, it takes some time for the adhesive to dry thereby lowering the productivity. Furthermore, hardening of the adhesive may shift the position of the wire-like optical wave-guide.
If a caulking is employed, when the amount of caulking force exceeds a predetermined magnitude, the wire-like optical wave-guide is broken, and, consequently, it is necessary to strictly control the application of the caulking force.